Folding knife



FIG. 1 is a left, top perspective view of a folding knife in an open configuration showing my new design;

FIG. 2 is a left-side elevation view thereof;

FIG. 3 is a right-side elevation view thereof;

FIG. 4 is a front elevation view thereof;

FIG. 5 is a back elevation view thereof;

FIG. 6 is a top plan view thereof;

FIG. 7 is a bottom plan view thereof;

FIG. 8 is a left, top perspective view of the folding knife in a closed configuration thereof; and,

FIG. 9 is a left-side elevation view thereof.

The broken lines depict environmental subject matter the forms no part of the claimed design. 

CLAIM The ornamental design for a folding knife, as shown and described. 